title: Respiratory viral detection and small airway inflammation in lung tissue of patients with stable, mild COPD.
abstract: BACKGROUND
  Viral respiratory tract infections are implicated in the pathogenesis of chronic obstructive pulmonary disease (COPD). In lung tissue specimens from patients with stable, mild COPD and from control smokers without airflow obstruction, we determined the prevalence and load of nucleic acid from common respiratory viruses and concomitant inflammation of small airways measuring less than 2-mm in diameter.
  
  
  METHODS
  Frozen lung tissue obtained from patients with stable, mild COPD (n = 20) and control subjects (n = 20) underwent real-time quantitative PCR (qPCR) for 13 respiratory viruses, and quantitative histology for inflammation of small airways. The two groups were compared for viral prevalence and load, and airway inflammation. The relationship between viral load and airway inflammatory cells was also analyzed.
  
  
  RESULTS
  Viral nucleic acid were detected in lung tissue of 18/40 (45.0%) of the individuals studied and included seven co-infections that were characterized by a "dominant virus" contributing to most of the total measured viral load. Lung tissue of COPD patients had a significantly higher prevalence of viral nucleic acid (particularly influenza A virus), and increased inflammation of small airways by macrophages and neutrophils versus controls. In qPCR-positive individuals, linear regression analysis showed a direct correlation between viral load and airway neutrophils, and between influenza A virus load and airway macrophages.
  
  
  CONCLUSIONS
  The lung tissue of patients with stable, mild COPD has a higher prevalence and load of respiratory viruses versus non-obstructed control subjects, and increased inflammation of small airways. Respiratory viruses may represent potential targets in COPD patient management.
authors.affiliation: 1UBC James Hogg Research Centre, Providence Heart-Lung Institute at St. Paul's Hospital, Departments of Medicine and Pathology and Laboratory Medicine, University of British Columbia, Vancouver, BC, Canada.
authors.forename: Soraya
authors.initials: S
authors.lastname: Utokaparch
authors.forename: Marc A
authors.initials: MA
authors.lastname: Sze
authors.forename: John V
authors.initials: JV
authors.lastname: Gosselink
authors.forename: John E
authors.initials: JE
authors.lastname: McDonough
authors.forename: W Mark
authors.initials: WM
authors.lastname: Elliott
authors.forename: James C
authors.initials: JC
authors.lastname: Hogg
authors.forename: Richard G
authors.initials: RG
authors.lastname: Hegele
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D056151:Airway Remodeling; D016022:Case-Control Studies; D002452:Cell Count; D005260:Female; D006801:Humans; D016676:Macrophages, Alveolar; D008297:Male; D008875:Middle Aged; D009504:Neutrophils; D029424:Pulmonary Disease, Chronic Obstructive / Q000473:pathology* / Q000821:virology*; D012141:Respiratory Tract Infections / Q000473:pathology* / Q000821:virology*; D012907:Smoking; D019562:Viral Load